Largest prime through the sum of primes raised to their respective prime powers

Believe it or not, S is a prime number !

More intriguing number facts.

Numbers Defying Ceiling and Floor Functions

Two sequences that agree for an embarrassingly long time.

Unlocking the Fraction

Use a trick to quickly and effortlessly determine the fraction that falls between 3/4 and 4/5.

show solution

Math & Art

In 1895, Nicholas Bogdanov-Belsky created the iconic painting “Mental Arithmetic in the Public School of S. Rachinsky,” now a classic. Students are depicted trying to solve the problem on the blackboard: (10²+11²+12²+13²+14²)/365. They seem to be having a great time!

A Curious Constant

A palindromic number is an integer that remains the same when its digits are reversed. The sum of the reciprocals of all the palindromic numbers in the world converges to approximately 3.3703…

φibonacci formula

Because Fn→ φ when n→ ∞

Perfect “Square” Circle

Numbers 1 to 32 are placed along the circumference of a circle without repeating any number and still the sum of any two adjacent numbers in this circle is a perfect square!